The annual Marxism festival began on Thursday of this week with a packed opening rally.
There was a positive and excited mood as speeches from trade unionists and campaigners gave a fitting end to a day when 1.4 million people had been on strike.
Mandy Brown, one of the strikers from Lambeth College, gave thanks for the solidarity that has helped make their fight possible. She announced that they had raised £35,000 for the strike fund.
There were cries of shame from the gallery when she told how the college principal had threatened to close key courses if workers re-balloted for more action.
Hillsborough campaigner Sheila Coleman talked about their struggle for justice. She also paid tribute to Gerry Conlon of the wrongly jailed Guildford Four who died last month, and urged everyone to stand up to Islamophobia.
Sheila said, "The Muslims of today are the Irish of yesterday".
Spontaneous chants of "Say it loud, say it clear, refugees are welcome here" erupted when asylum seeker Manjeet Kaur addressed the rally.
Maz Saleem, whose father was murdered by a racist in Birmingham, explained that the man who killed him and tried to bomb mosques is not being treated like a terrorist.
"Why?" she asked. "Because only Muslims can be terrorists."
Ian Hodson, president of the Bfawu bakers' union, told the rally about the sustained strike that beat zero hours contracts at Hovis in Wigan last year.
"When they say striking doesn't work, tell them about the Hovis workers," he said.
Perhaps the largest standing ovation was reserved for striking South African miner Makhanya Siphamandla.
He told how being imprisoned by the government for three weeks hadn't broken his spirits, and how he was hopeful for the future.
"The working class in South Africa feel their power now," he said. "The strike has motivated other workers"
Makhanya explained that he had learned a valuable lesson on the strike. "The workers were never short of power. They were short of leadership"
Jess Edwards a teacher from south London spoke about how proud she was to be striking today.
She explained that for teachers the strike was not just about pay. It was about standing up to the bullying of Ofsted and Michael Gove's racism.
Socialist Worker editor Judith Orr closed the rally on a triumphant note.
She said, "The important part of today was to show that the working class is still here and still fighting".
Marxism is a five day event in central London. Around 200 debates, meetings, book launches and film showings will discuss a world in crisis and how to change it.
Tickets can still be bought at the door.